Enamel is one of the most durable paints available. Metal is one of the most durable materials available. Therefore, painting metal with enamel will result in a very durable object, regardless of what the object is. As long as you pay attention to the preparation of your metal before painting, you will end up with professional-looking results for very little money and time spent.
Sand or wire brush the metal object to remove any peeling paint, loose previous coating or rust spots.
Spray water from the sink or garden hose onto the metal object to thoroughly remove any sanding dust. Allow the metal object to dry.
Lay newspapers or a dust sheet carefully on an outdoor or garage work surface, as over spray from spray paint cannot be easily removed.
Apply the solvent or acid to the entire metal surface with the rag. Use a toothbrush to reach into crevices. The solvent will remove any oils or difficult debris to further prepare the surface of the metal. Allow the solvent to dry.
Spray a thin coat of primer onto the object. Be sure to use wide, sweeping strokes to prevent the primer from pooling and dripping. Spray paint comes out fast, so you may wish to practice your spray technique on a piece of cardboard first. Be sure to thoroughly coat the entire metal object with primer.
Allow the primer to dry for several hours or overnight.
Spray a thin coat of enamel onto the metal object, using the same technique you used with the primer.
Allow the enamel to dry overnight, and then add another coat of enamel. Allow to dry overnight again before using the metal object.
Do not use spray paints indoors. The fumes are such that proper ventilation is best accomplished outside or in a garage with the garage door wide open.